Function of the Anterior Band of the Inferior Glenohumeral Ligament During the Load and Shift Test

The anterior band of the inferior glenohumeral ligament (AB-IGHL) plays a crucial role in anterior shoulder stability. This capsulo-ligamentous structure originates on the anterior edge of the glenoid and labrum and inserts on the anterior/lateral edge of the articular surface of the humeral head. AB-IGHL detachment from the anterior glenoid and labrum (Bankart lesion) as well as capsular stretching are frequent injuries for which initial diagnosis is often difficult. The load and shift test is a clinical exam used to assess the magnitude of anterior instability by applying an anterior load to the humeral head with the shaft in 60 degrees of abduction [1]. Information on the magnitudes and distribution of stress and strain can help in the interpretation of motion during the exam as well as assist in localizing instabilities to particular regions of the capsule. The objectives of this study were to examine the stress and strain in the AB-IGHL during the load and shift test using finite element (FE) modeling techniques.